I'm in the young cohort, and it's frankly insane how many of my friends consider starting a conversation with a stranger in public to be almost sinful in basically every context. Bars are still acceptable, but for basically every other public place I've heard them complain, one way or another, about someone trying to start a conversation with them. Not about them not taking no for an answer, just being annoyed that they tried.

Now, I know it's "not every young person", since I also know many social butterflies, but the number I know is still shocking.